uclibc-ng/libpthread/nptl/sysdeps/unix/sysv/linux/arm/sysdep.h

/* Copyright (C) 1992, 93, 1995-2000, 2002, 2003, 2005, 2006
   Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>, August 1995.
   ARM changes by Philip Blundell, <pjb27@cam.ac.uk>, May 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#ifndef _LINUX_ARM_SYSDEP_H
#define _LINUX_ARM_SYSDEP_H 1

#include <sys/syscall.h>

/* There is some commonality.  */
#include <sysdeps/arm/sysdep.h>

/* For Linux we can use the system call table in the header file
	/usr/include/asm/unistd.h
   of the kernel.  But these symbols do not follow the SYS_* syntax
   so we have to redefine the `SYS_ify' macro here.  */
#undef SYS_ify
#define SWI_BASE  (0x900000)
#define SYS_ify(syscall_name)	(__NR_##syscall_name)


#ifdef __ASSEMBLER__

/* Linux uses a negative return value to indicate syscall errors,
   unlike most Unices, which use the condition codes' carry flag.

   Since version 2.1 the return value of a system call might be
   negative even if the call succeeded.  E.g., the `lseek' system call
   might return a large offset.  Therefore we must not anymore test
   for < 0, but test for a real error by making sure the value in R0
   is a real error number.  Linus said he will make sure the no syscall
   returns a value in -1 .. -4095 as a valid result so we can safely
   test with -4095.  */

#undef	PSEUDO
#define	PSEUDO(name, syscall_name, args)				      \
  .text;								      \
  ENTRY (name);								      \
    DO_CALL (syscall_name, args);					      \
    cmn r0, $4096;

#define PSEUDO_RET							      \
    RETINSTR(cc, lr);							      \
    b PLTJMP(SYSCALL_ERROR)
#undef ret
#define ret PSEUDO_RET

#undef	PSEUDO_END
#define	PSEUDO_END(name)						      \
  SYSCALL_ERROR_HANDLER							      \
  END (name)

#undef	PSEUDO_NOERRNO
#define	PSEUDO_NOERRNO(name, syscall_name, args)			      \
  .text;								      \
  ENTRY (name);								      \
    DO_CALL (syscall_name, args);

#define PSEUDO_RET_NOERRNO						      \
    DO_RET (lr);

#undef ret_NOERRNO
#define ret_NOERRNO PSEUDO_RET_NOERRNO

#undef	PSEUDO_END_NOERRNO
#define	PSEUDO_END_NOERRNO(name)					      \
  END (name)

/* The function has to return the error code.  */
#undef	PSEUDO_ERRVAL
#define	PSEUDO_ERRVAL(name, syscall_name, args) \
  .text;								      \
  ENTRY (name)								      \
    DO_CALL (syscall_name, args);					      \
    rsb r0, r0, #0

#undef	PSEUDO_END_ERRVAL
#define	PSEUDO_END_ERRVAL(name) \
  END (name)

#define ret_ERRVAL PSEUDO_RET_NOERRNO

#if NOT_IN_libc
# define SYSCALL_ERROR __local_syscall_error
# ifdef RTLD_PRIVATE_ERRNO
#  define SYSCALL_ERROR_HANDLER					\
__local_syscall_error:						\
       ldr     r1, 1f;						\
       rsb     r0, r0, #0;					\
0:     str     r0, [pc, r1];					\
       mvn     r0, #0;						\
       DO_RET(lr);						\
1:     .word C_SYMBOL_NAME(rtld_errno) - 0b - 8;
# else
#  define SYSCALL_ERROR_HANDLER					\
__local_syscall_error:						\
	str	lr, [sp, #-4]!;					\
	str	r0, [sp, #-4]!;					\
	bl	PLTJMP(C_SYMBOL_NAME(__errno_location)); 	\
	ldr	r1, [sp], #4;					\
	rsb	r1, r1, #0;					\
	str	r1, [r0];					\
	mvn	r0, #0;						\
	ldr	pc, [sp], #4;
# endif
#else
# define SYSCALL_ERROR_HANDLER	/* Nothing here; code in sysdep.S is used.  */
# define SYSCALL_ERROR __syscall_error
#endif

/* Linux takes system call args in registers:
	syscall number	in the SWI instruction
	arg 1		r0
	arg 2		r1
	arg 3		r2
	arg 4		r3
	arg 5		r4	(this is different from the APCS convention)
	arg 6		r5
	arg 7		r6

   The compiler is going to form a call by coming here, through PSEUDO, with
   arguments
	syscall number	in the DO_CALL macro
	arg 1		r0
	arg 2		r1
	arg 3		r2
	arg 4		r3
	arg 5		[sp]
	arg 6		[sp+4]
	arg 7		[sp+8]

   We need to shuffle values between R4..R6 and the stack so that the
   caller's v1..v3 and stack frame are not corrupted, and the kernel
   sees the right arguments.

*/

#undef	DO_CALL
#if defined(__ARM_EABI__)
#define DO_CALL(syscall_name, args)		\
    DOARGS_##args				\
    mov ip, r7;					\
    ldr r7, =SYS_ify (syscall_name);		\
    swi 0x0;					\
    mov r7, ip;					\
    UNDOARGS_##args
#else
#define DO_CALL(syscall_name, args)		\
    DOARGS_##args				\
    swi SYS_ify (syscall_name); 		\
    UNDOARGS_##args
#endif

#define DOARGS_0 /* nothing */
#define DOARGS_1 /* nothing */
#define DOARGS_2 /* nothing */
#define DOARGS_3 /* nothing */
#define DOARGS_4 /* nothing */
#define DOARGS_5 str r4, [sp, $-4]!; ldr r4, [sp, $4];
#define DOARGS_6 mov ip, sp; stmfd sp!, {r4, r5}; ldmia ip, {r4, r5};
#define DOARGS_7 mov ip, sp; stmfd sp!, {r4, r5, r6}; ldmia ip, {r4, r5, r6};

#define UNDOARGS_0 /* nothing */
#define UNDOARGS_1 /* nothing */
#define UNDOARGS_2 /* nothing */
#define UNDOARGS_3 /* nothing */
#define UNDOARGS_4 /* nothing */
#define UNDOARGS_5 ldr r4, [sp], $4;
#define UNDOARGS_6 ldmfd sp!, {r4, r5};
#define UNDOARGS_7 ldmfd sp!, {r4, r5, r6};

#else /* not __ASSEMBLER__ */

/* Define a macro which expands into the inline wrapper code for a system
   call.  */
#undef INLINE_SYSCALL
#define INLINE_SYSCALL(name, nr, args...)				\
  ({ unsigned int _sys_result = INTERNAL_SYSCALL (name, , nr, args);	\
     if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_sys_result, ), 0))	\
       {								\
	 __set_errno (INTERNAL_SYSCALL_ERRNO (_sys_result, ));		\
	 _sys_result = (unsigned int) -1;				\
       }								\
     (int) _sys_result; })

#undef INTERNAL_SYSCALL_DECL
#define INTERNAL_SYSCALL_DECL(err) do { } while (0)

#undef INTERNAL_SYSCALL_RAW
#if defined(__thumb__)
/* Hide the use of r7 from the compiler, this would be a lot
 * easier but for the fact that the syscalls can exceed 255.
 * For the moment the LOAD_ARG_7 is sacrificed.
 * We can't use push/pop inside the asm because that breaks
 * unwinding (ie. thread cancellation).
 */
#define INTERNAL_SYSCALL_RAW(name, err, nr, args...)		\
  ({ unsigned int _sys_result;                                  \
    {                                                           \
      int _sys_buf[2];						\
      register int _a1 __asm__ ("a1");                          \
      register int *_v3 __asm__ ("v3") = _sys_buf;		\
      LOAD_ARGS_##nr (args)                                     \
      *_v3 = (int) (name);					\
      __asm__ __volatile__ ("str	r7, [v3, #4]\n"		\
                    "\tldr      r7, [v3]\n"                     \
                    "\tswi      0       @ syscall " #name "\n"  \
                    "\tldr      r7, [v3, #4]"                   \
                   : "=r" (_a1)                                 \
                    : "r" (_v3) ASM_ARGS_##nr                   \
                    : "memory");                                \
      _sys_result = _a1;                                        \
    }                                                           \
    (int) _sys_result; })
#elif defined(__ARM_EABI__)
#define INTERNAL_SYSCALL_RAW(name, err, nr, args...)		\
  ({unsigned int _sys_result;					\
     {								\
       register int _a1 __asm__ ("r0"), _nr __asm__ ("r7");	\
       LOAD_ARGS_##nr (args)					\
       _nr = name;						\
       __asm__ __volatile__ ("swi	0x0 @ syscall " #name	\
		     : "=r" (_a1)				\
		     : "r" (_nr) ASM_ARGS_##nr			\
		     : "memory");				\
       _sys_result = _a1;					\
     }								\
     (int) _sys_result; })
#else /* !defined(__ARM_EABI__) */
#define INTERNAL_SYSCALL_RAW(name, err, nr, args...)		\
  ({ unsigned int _sys_result;					\
     {								\
       register int _a1 __asm__ ("a1");				\
       LOAD_ARGS_##nr (args)					\
       __asm__ __volatile__ ("swi	%1 @ syscall " #name	\
		     : "=r" (_a1)				\
		     : "i" (name) ASM_ARGS_##nr			\
		     : "memory");				\
       _sys_result = _a1;					\
     }								\
     (int) _sys_result; })
#endif

#undef INTERNAL_SYSCALL
#define INTERNAL_SYSCALL(name, err, nr, args...)		\
	INTERNAL_SYSCALL_RAW(SYS_ify(name), err, nr, args)

#undef INTERNAL_SYSCALL_ARM
#define INTERNAL_SYSCALL_ARM(name, err, nr, args...)		\
	INTERNAL_SYSCALL_RAW(__ARM_NR_##name, err, nr, args)

#undef INTERNAL_SYSCALL_ERROR_P
#define INTERNAL_SYSCALL_ERROR_P(val, err) \
  ((unsigned int) (val) >= 0xfffff001u)

#undef INTERNAL_SYSCALL_ERRNO
#define INTERNAL_SYSCALL_ERRNO(val, err)	(-(val))

#define LOAD_ARGS_0()
#define ASM_ARGS_0
#define LOAD_ARGS_1(a1)				\
  _a1 = (int) (a1);				\
  LOAD_ARGS_0 ()
#define ASM_ARGS_1	ASM_ARGS_0, "r" (_a1)
#define LOAD_ARGS_2(a1, a2)			\
  register int _a2 __asm__ ("a2") = (int) (a2);	\
  LOAD_ARGS_1 (a1)
#define ASM_ARGS_2	ASM_ARGS_1, "r" (_a2)
#define LOAD_ARGS_3(a1, a2, a3)			\
  register int _a3 __asm__ ("a3") = (int) (a3);	\
  LOAD_ARGS_2 (a1, a2)
#define ASM_ARGS_3	ASM_ARGS_2, "r" (_a3)
#define LOAD_ARGS_4(a1, a2, a3, a4)		\
  register int _a4 __asm__ ("a4") = (int) (a4);	\
  LOAD_ARGS_3 (a1, a2, a3)
#define ASM_ARGS_4	ASM_ARGS_3, "r" (_a4)
#define LOAD_ARGS_5(a1, a2, a3, a4, a5)		\
  register int _v1 __asm__ ("v1") = (int) (a5);	\
  LOAD_ARGS_4 (a1, a2, a3, a4)
#define ASM_ARGS_5	ASM_ARGS_4, "r" (_v1)
#define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6)	\
  register int _v2 __asm__ ("v2") = (int) (a6);	\
  LOAD_ARGS_5 (a1, a2, a3, a4, a5)
#define ASM_ARGS_6	ASM_ARGS_5, "r" (_v2)
#define LOAD_ARGS_7(a1, a2, a3, a4, a5, a6, a7)	\
  register int _v3 __asm__ ("v3") = (int) (a7);	\
  LOAD_ARGS_6 (a1, a2, a3, a4, a5, a6)
#define ASM_ARGS_7	ASM_ARGS_6, "r" (_v3)

#if defined(__ARM_EABI__)
#undef INTERNAL_SYSCALL_NCS
#define INTERNAL_SYSCALL_NCS(number, err, nr, args...)		\
	INTERNAL_SYSCALL_RAW(number, err, nr, args)
#else
/* We can't implement non-constant syscalls directly since the syscall
   number is normally encoded in the instruction.  So use SYS_syscall.  */
#undef INTERNAL_SYSCALL_NCS
#define INTERNAL_SYSCALL_NCS(number, err, nr, args...)		\
	INTERNAL_SYSCALL_NCS_##nr (number, err, args)

#define INTERNAL_SYSCALL_NCS_0(number, err, args...)		\
	INTERNAL_SYSCALL (syscall, err, 1, number, args)
#define INTERNAL_SYSCALL_NCS_1(number, err, args...)		\
	INTERNAL_SYSCALL (syscall, err, 2, number, args)
#define INTERNAL_SYSCALL_NCS_2(number, err, args...)		\
	INTERNAL_SYSCALL (syscall, err, 3, number, args)
#define INTERNAL_SYSCALL_NCS_3(number, err, args...)		\
	INTERNAL_SYSCALL (syscall, err, 4, number, args)
#define INTERNAL_SYSCALL_NCS_4(number, err, args...)		\
	INTERNAL_SYSCALL (syscall, err, 5, number, args)
#define INTERNAL_SYSCALL_NCS_5(number, err, args...)		\
	INTERNAL_SYSCALL (syscall, err, 6, number, args)
#endif

#endif	/* __ASSEMBLER__ */

#endif /* linux/arm/sysdep.h */